Projector having a position adjusting device that moves the projection optical device

ABSTRACT

A projector includes: a projection position adjusting device that adjusts a projection position of a projection optical device. The projection position adjusting device includes: adjusting and driving units that move a first moving plate and a second moving plate. The adjusting and driving unit include: a pair of worms that have a columnar shape and have threads on outer circumferences thereof; and a pair of sliders that are screwed in the pair of worms, respectively. The pair of worms are disposed to extend along the first direction or the second direction. One of the sliders engages with one of moving plates. Engaging structures including inclining engaging holes that extend in a direction crossing the direction in the plane orthogonal to the projecting direction and engaging projections inserted through the inclining engaging holes are provided in the other slider and the other moving plate.

BACKGROUND

1. Technical Field

The present invention relates to a projector.

2. Related Art

There is known a projector that modulates, according to image information, a light beam emitted from a light source and magnifies and projects the light beam on a screen using a projection optical device.

In such a projector, the light beam is tilt-projected upward with the projector fixed in a low position, tilt-projected downward with the projector fixed in a high position, and, besides the projection in the vertical direction, tilt-projected in the horizontal direction. Therefore, there is known a projector including a projection position adjusting device (a lens shift mechanism) that moves, with respect to an optical system such as an optical modulation device, a projection optical device in a direction orthogonal to a direction in which a light beam is irradiated (a projecting direction) (see, for example JP-A-2004-245956, FIGS. 2 to 4).

In the projection position adjusting device disclosed in JP-A-2004-245956, a projection lens unit (a projection optical device) is fixed to a lens holder and moved in the vertical direction and the horizontal direction together with the lens holder by two driving mechanism units.

As the driving mechanism units, worms disposed to be orthogonal to each other are adopted. A rotating shaft to which a pair of pinions are fastened is rotated to move the lens holder engaged with the pair of pinions by rotating the worms.

In the projection position adjusting device disclosed in JP-A-2004-245956, the pair of worms are disposed to be orthogonal to each other. Therefore, for example, when dials operated by a user are provided at one ends of the pair of worms, respectively, it is difficult to expose the respective dials from the same end face (e.g., the top) of an armor housing configuring the projector.

In order to expose the respective dials from the same end face of the armor housing, as described in JP-A-2004-245956, a rotating shaft of the dials (knob sections) and a rotating shaft of the worms are disposed to be orthogonal to each other and the dials and the worms are connected by a pair of spiral gears. The rotating force of the dials is converted into the rotating force of the worms by the pair of spiral gears. In such a configuration, it is necessary to provide a transmission converting mechanism such as the pair of spiral gears. Therefore, simplification of the structure cannot be realized.

SUMMARY

An advantage of some aspect of the invention is to provide a projector that can realize simplification of the structure of a projection position adjusting device and realize improvement of convenience in adjusting a projection position.

According to an aspect of the invention, there is provided a projector including: a projection optical device that magnifies and projects image light; and a projection position adjusting device that moves the projection optical device in a plane orthogonal to a projecting direction and adjusts a projection position of the projection optical device. The projection position adjusting device includes: a first moving plate that supports the projection optical device and moves in a first direction and a second direction orthogonal to each other in the plane orthogonal to the projecting direction; a second moving plate that engages with the first moving plate and moves in the second direction together with the first moving plate; adjusting and driving units that move the first moving plate and the second moving plate; and a fixed member that is fixed in the projector and supports the moving plates and the adjusting and driving units. The adjusting and driving unit include: a pair of worms that have a columnar shape and have threads on outer circumferences thereof; and a pair of sliders that are screwed in the pair of worms, respectively, and move in an extending direction of the worms according to the rotation of the worms. The pair of worms are disposed to extend along the first direction or the second direction. One of the sliders engages with one of moving plates to move in the extending direction of the worms together with the one moving plate. Engaging structures including inclining engaging holes that extend in a direction crossing the direction in the plane orthogonal to the projecting direction and engaging projections inserted through the inclining engaging holes are provided in the other slider and the other moving plate.

In the following explanation, for simplification of explanation, the “first direction” is set in a direction of the vertical axis (an up to down direction) and the “second direction” is set in a direction of the horizontal axis (a left to right direction). The “worms” are disposed to extend along the first direction (the up to down direction). “One moving plate” and “the other moving plate” correspond to the “first moving plate” and the “second moving plate”. “One slider” and “the other slider” are described as “first slider” and “second slider” in association with “one moving plate (the first moving plate” and “the other moving plate (the second moving plate)”. The “pair of worms” are described by using the same ordinal numbers as the sliders.

In the aspect of the present invention, the adjusting and driving units include the pair of worms disposed to extend in the up to down direction, i.e., arranged parallel to each other. Consequently, for example, if dials operated by a user are provided at one ends on an upper side of the pair of worms, respectively, it is possible to expose the dials from the same end (the top) of an armor housing. Therefore, operability of the projection position adjusting device is improved and improvement of convenience in adjusting a projection position can be realized.

The adjusting and driving units include the pair of sliders. The first slider engages with the first moving plate to move in the up to down direction together with the first moving plate. The engaging structures having the inclining engaging holes and the engaging projections are provided in the second slider and the second moving plate. Consequently, if the first worm is rotated, the first moving plate moves in the up to down direction together with the first slider and the projection position of the projection optical device supported by the first supporting plate can be changed in the up to down direction. If the second worm is rotated, the engaging projections are guided by the inclining engaging holes according to the movement in the up to down direction of the second slider, the first moving plate moves in the left to right direction together with the second moving plate, and the projection position can be moved in the left to right direction. Therefore, even when the dials are exposed from the same end face of the armor housing, it is possible to adjust the projection position without providing the transmission converting mechanism such as the pair of spiral gears in the past. Therefore, simplication of the structure can be realized.

Preferably, the one slider has a flat first end face opposed to the worm, thread grooves that screw with the worm are formed in the first end face, and the adjusting and driving units include a first rail member that is connected to the fixed member, engages with the one slider, and guides the movement of the one slider and a first urging member that is interposed between the first rail member and the fixed member and urges the first rail member to the one slider.

When the own weight of the projection optical device is applied in the first direction (the up to down direction) by the impact due to drop of the projector or the like, force is applied to the first slider that engages with the first moving plate that supports the projection optical device. Therefore, the thread grooves of the first slider, the threads of the first worm, and the like tend to be damaged.

In the aspect of the present invention, in the first slider, the thread grooves are formed in the flat first end face. The adjusting and driving units include the first rail member and the first urging member that urges the first rail member to the first slider, i.e., urges the first slider to the first worm via the first rail member. Consequently, when force is applied to the first slider in the first direction (the up to down direction) by the impact due to the drop of the projector or the like, the first slider slips out of the threads of the first worm and moves in the extending direction of the first worm (the first direction (the up to down direction)) while moving in a direction away from the first worm against the urging force generated by the first urging member. Therefore, even in the case described above, it is possible to prevent the thread grooves of the first slider, the threads of the first worm, and the like from being damaged.

Preferably, the other slider has a flat second end face opposed to the worm, thread grooves that screw with the worm are formed in the second end face, the adjusting and driving units include a second rail member that is connected to the fixed member, engages with the other slider, and guides the movement of the other slider and a second urging member that is interposed between the second rail member and the fixed member and urges the second rail member to the other slider, engaging structures that extend along the worm and have a convex section and a concave section engaging with each other are provided in the other slider and the second rail member, and, in at least one of the convex section and the concave section, slopes are formed in at both ends that cross in a direction orthogonal to the extending direction of the worm.

When the own weight of the projection optical device is applied in the second direction (the up to down direction) by the impact due to drop of the projector or the like, force is applied to the second slider that engages with the second moving plate moving in the left to right direction together with the first moving plate that supports the projection optical device. Therefore, the thread grooves of the second slider, the threads of the second worm, and the like tend to be damaged.

In the aspect of the present invention, in the second slider, the thread grooves are formed in the flat second end face. The adjusting and driving units include the second rail member and the second urging member that urges the second rail member to the second slider, i.e., urges the second slider to the second worm via the second rail member. The slopes are formed in at least one of the convex section and the concave section configuring the engaging structures provided in the second slider and the second worm. Consequently, when force is applied to the second slider in the second direction (the left to right direction) by the impact due to the drop of the projector or the like, the second slider slips out of the threads of the second worm by the slopes and moves in the direction orthogonal to the extending direction of the second worm (the second direction (the left to right direction)) while moving in a direction away from the second worm against the urging force generated by the second urging member. Therefore, even in the case described above, it is possible to prevent the thread grooves of the second slider, the threads of the second worm, and the like from being damaged.

Preferably, the other moving plate is arranged to be interposed between the fixed member and the one moving plate, the inclining engaging hole is provided in the other slider, the engaging projection is provided in the other moving plate, and engaging structures having guide engaging holes and guide projections that are located on a straight line crossing a center axis of the engaging projection and extending along the moving direction of the other moving plate, engage with each other, and guide the movement of the other moving plate with respect to the fixed member are provided in the other moving plate and the fixed member.

In the aspect of the present invention, the guide engaging holes and the guide projections configuring the engaging structures provided in the second moving plate and the fixed member are located on the straight line crossing the center axis of the engaging projections, which receive force from the second slider, and extending along the moving direction of the second moving plate (the second direction (the left to right direction)). Consequently, when the second moving plate moves according to the movement of the second slider, the second moving plate does not rotate in the plane orthogonal to the projecting direction and it is possible to smoothly move the second moving plate in the second direction (the left to right direction) using the guide engaging holes and the guide engaging projections.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements.

FIG. 1 is a perspective view of an external appearance of a projector according to an embodiment of the invention.

FIG. 2 is a schematic diagram of an apparatus main body housed in an armor housing according to the embodiment.

FIG. 3 is a perspective view of the structure of a projection position adjusting device according to the embodiment.

FIG. 4 is a perspective view of the structure of the projection position adjusting device according to the embodiment.

FIG. 5 is a disassembled perspective view of a lens connecting unit and a first moving plate according to the embodiment viewed from the front side.

FIG. 6 is a disassembled perspective view of a second moving plate, a fixed member, a first adjusting and driving unit, and a second adjusting and driving unit according to the embodiment viewed from the front side.

FIG. 7 is a longitudinal sectional view of the structure of the first adjusting and driving unit according to the embodiment.

FIG. 8 is a transverse sectional view of the structure of the second adjusting and driving unit according to the embodiment.

FIG. 9 is a disassembled perspective view of the first moving plate attached to the fixed member by four coupling members according to the embodiment viewed from the front side.

FIGS. 10A and 10B are diagrams for explaining an up to down motion according to the embodiment.

FIGS. 11A and 11B are diagrams for explaining the up to down motion according to the embodiment.

FIGS. 12A and 12B are diagrams for explaining a left to right motion according to the embodiment.

FIGS. 13A and 13B are diagrams for explaining the left to right motion according to the embodiment.

DESCRIPTION OF EXEMPLARY EMBODIMENTS

An embodiment of the invention is explained below with reference to the accompanying drawings.

External Structure

FIG. 1 is a perspective view of an external appearance of a projector 1 according to this embodiment. Specifically, FIG. 1 is a perspective view of the projector 1 set on a desk or the like viewed from the front upper side.

“Up”, “down”, “left”, and “right” described below correspond to up, down, the left, and the right in the view shown in FIG. 1. “Front” and “back” described below correspond to the front and the back in the view shown in FIG. 1.

The projector 1 modulates, according to image information, a light beam emitted from a light source, forms image light, and magnifies and projects the formed image light on a screen (not shown). As shown in FIG. 1, the projector 1 includes an armor housing 2 that configures an armor.

The armor housing 2 houses an apparatus main body of the projector 1. As shown in FIG. 1, the armor housing 2 includes an upper case 21 that forms the top, the front, the back, and the sides of the projector 1 and a lower case 22 that forms the bottom, the front, the back, and the sides of the projector 1.

In the upper case 21, as shown in FIG. 1, a first dial 111 and a second dial 121, which configure a projection position adjusting device 5, are exposed to the top.

When the dials 111 and 121 are rotated by a user, a projection lens 3 moves in an up to down direction and a left to right direction and a position of a projected image (a projection position) on the screen is adjusted.

The detailed structure of the projection position adjusting device 5 is explained later.

Internal Structure

FIG. 2 is a schematic diagram of the apparatus main body housed in the armor housing 2. The apparatus main body shown in FIG. 2 is housed in the armor housing 2. The apparatus main body includes the projection lens 3 as a projection optical device, an optical unit 4, and the projection position adjusting device 5.

Although not specifically shown in the figure, in the armor housing 2, a cooling unit including a cooling fan that cools the inside of the projector 1, a power supply unit that supplies electric power to members of the projector 1, a control device that controls operations of the members of the projector 1, and the like are arranged in a space excluding the members 3 to 5.

Structure of the Projection Lens

As shown in FIG. 1, a distal end of the projection lens 3 is exposed from a substantial center portion in the front of the armor housing 2. The projection lens 3 magnifies and projects image light formed by the optical unit 4 on the screen.

Although not specifically shown in the figure, the projection lens 3 is configured as a set lens in which plural lenses are housed in a lens barrel 31 (see FIG. 5).

The projection lens 3 is connected to the projection position adjusting device 5 by three attachment projections 311 (see FIG. 5) formed on a proximal end side of the lens barrel 31 and is supported by the projection position adjusting device 5.

Structure of the Optical Unit

The optical unit 4 optically processes a light beam emitted from the light source and forms image light corresponding to image information under the control by the control device. As shown in FIG. 2, the optical unit 4 includes a light source device 41, an illumination optical device 42, a color-separation optical device 43, a relay optical device 44, an optical device 45, and an optical component housing 46 that houses the optical components 41 to 45.

As shown in FIG. 2, the light source device 41 includes a light source 411 and a reflector 412. In the light source device 41, an emitting direction of a light beam emitted from the light source 411 is aligned by the reflector 412. The light source device 41 emits the light beam to the illumination optical device 42.

As shown in FIG. 2, the illumination optical device 42 includes a first lens array 421, a second lens array 422, a polarization converting element 423, and a superimposing lens 424. The light beam emitted from the light source device 41 is divided into plural partial light beams by the first lens array 421 and focused near the second lens array 422. The partial light beams emitted from the second lens array 422 are made incident on an incident surface of the polarization converting element 423 such that a center axis (a main beam) thereof is perpendicular to the incident surface. The partial light beams are emitted by the polarization converting element 423 as a substantially one kind of linear polarized light. The plural partial light beams emitted from the polarization converting element 423 as the linear polarized light and transmitted through the superimposing lens 424 are superimposed on three liquid crystal panels 451 of the optical device 45 explained later.

As shown in FIG. 2, the color-separation optical device 43 includes two dichroic mirrors 431 and 432 and a reflection mirror 433. The color-separation optical device 43 has a function of separating the plural partial light beams emitted from the illumination optical device 42 into color lights of three colors, red, green, and blue, using the dichroic mirrors 431 and 432 and the reflection mirror 433.

As shown in FIG. 2, the relay optical device 44 includes an incidence side lens 441, a relay lens 443, and reflection mirrors 442 and 444. The relay optical device 44 has a function of guiding the color lights separated by the color-separation optical device 43, for example, the red light to a liquid crystal panel 451R of the optical device 45 on a red light side explained later.

The optical device 45 modulates an incident light beam according to image information and forms image light. As shown in FIG. 2, the optical device 45 includes liquid crystal panels 451 (a liquid crystal panel 451R on a red light side, a liquid crystal panel 451G on a green light side, and a liquid crystal panel 451B on a blue light side) as three optical modulation devices, incidence side sheet polarizers 452 arranged on an optical path pre-stage side of the liquid crystal panels 451, emission side sheet polarizers 453 arranged on an optical path post-stage side of the liquid crystal panels 451, and a cross dichroic prism 454 as a color-combination optical device.

The three incidence side sheet polarizers 452 transmit only polarized light having a polarization direction substantially the same as a polarization direction aligned by the polarization converting element 423 among the light beams separated by the color-separation optical device 43 and absorb the other light beams. The incidence side sheet polarizers 452 are configured by sticking polarization films on transmissive substrates.

The three liquid crystal panels 451 are formed by enclosing liquid crystal as an electro-optical substance in a pair of transparent glass substrates. An orientation state of the liquid crystal is controlled according to a driving signal from the control device. The liquid crystal panels 451 modulate the polarizing direction of the polarized light emitted from the incidence side sheet polarizers 452.

The three emission side sheet polarizers 453 have a function substantially the same as that of the incidence side sheet polarizers 452. The emission side sheet polarizers 453 transmit polarized light in a fixed direction among the light beams emitted via the liquid crystal panels 451 and absorb the other light beams.

The cross dichroic prism 454 combines the color lights modulated for each of the color lights emitted from the emission side sheet polarizers 453 and forms a color image. The cross dichroic prism 454 is formed in a substantial square shape in plan view obtained by bonding four rectangular prisms. Two dielectric multilayer films are formed in interfaces where the rectangular prisms are bonded. The dielectric multilayer films transmit the color light emitted from the liquid crystal panel 451G and transmitted through the emission side sheet polarizer 453 and reflect the color lights emitted from the liquid crystal panels 451R and 451B and transmitted through the emission side sheet polarizers 453. In this way, the color lights are combined and image light is formed. The image light formed by the cross dichroic prism 454 is emitted to the projection lens 3.

Structure of the Projection Position Adjusting Device

FIGS. 3 and 4 are perspective views of the structure of the projection position adjusting device 5. Specifically, FIG. 3 is a perspective view of the projection position adjusting device 5 viewed from the front side and FIG. 4 is a perspective view of the projection position adjusting device 5 viewed from the back side.

The projection position adjusting device 5 supports the projection lens 3 and moves the projection lens 3 in the up to down direction and the left to right direction to adjust a projection position of the projection lens 3. As shown in FIG. 3 or FIG. 4, the projection position adjusting device 5 includes a lens connecting unit 6, a first moving plate 7, a second moving plate 8 (FIG. 3), a fixed member 9, a first adjusting and driving unit 11, a second adjusting and driving unit 12 (FIG. 3), and four coupling members 13 (FIG. 4).

Structure of the Lens Connecting Unit

FIG. 5 is a disassembled perspective view of the lens connecting unit 6 and the first moving plate 7 viewed from the front side.

The lens connecting unit 6 is a member to which the projection lens 3 is connected. As shown in FIG. 5, the lens connecting unit 6 includes a tabular section 61 that has a lens through hole 611 substantially in the center thereof and a projecting section 62 of a cylindrical frame shape that extends from a circumferential portion of the lens through hole 611 to the back side of the tabular section 61. The lens through hole 611 includes a first lens through hole 6111 that is located on the front side and has a dimension larger than an outer diameter dimension of the lens barrel 31 and a second lens through hole 6112 that is located on the back side and has a dimension substantially the same as the outer diameter dimension of the lens barrel 31. The lens through hole 611 is formed in a stepped shape from the front side to the back side.

Three attachment recesses 6112R are formed in association with the three attachment projections 311 in an inner circumference of the second lens through hole 6112.

The three attachment recesses 6112A are formed in a substantial L shape by being cut out from the front side to the back side to be substantially flush with an inner circumference of the first lens through hole 6111 and cut out clockwise viewed from the front side around a center axis of the lens through hole 611.

With the configuration explained above, when the projection lens 3 is inserted through the lens through hole 611 with the three attachment projections 311 fit in the three attachment recesses 6112A and the projection lens 3 is rotated clockwise viewed from the front side, the projection lens 3 is connected to the lens connecting unit 6. In other words, the projection lens 3 and the lens connecting unit 6 are connected in the structure of a so-called bayonet type.

The lens connecting unit 6 is fixed by the first moving plate 7 by fixing screws 6R in four positions surrounding the lens through hole 611.

Structure of the First Moving Plate

As shown in FIG. 5, the first moving plate 7 is made of a plate member of a substantial rectangular shape in plan view. The first moving plate 7 is movable in the up to down direction (the first direction) and the left to right direction (the second direction) with an end face on the back side thereof coming into contact with the fixed member 9. The first moving plate 7 supports the projection lens 3 via the lens connecting unit 6 and moves to move the projection lens 3 in the up to down direction and the left to right direction.

In the first moving plate 7, an opening 71 that has a dimension substantially the same as the outer diameter dimension of the lens barrel 31 and allows the proximal end of the lens barrel 31 to be inserted through is formed substantially in the center thereof.

In the first moving plate 7, two projections 72 a are formed substantially in the center in the up to down direction in the right side. A section between the projections 72A functions as an engaging recess 72 for engaging with a first slider 113 explained later that configures the first adjusting and driving unit 11.

Further, in the first moving plate 7, two first guide engaging holes 73 (see FIGS. 10A and 10B and FIGS. 11A and 11B) that are located on the right side near the engaging recess 72, extend along the up to down direction, and engage with the second moving plate 8 are formed in an end face on the back side.

Moreover, in the first moving plate 7, cylindrical coupling projections 74 are formed in four corner positions in the end face on the back side. Although not specifically shown in the figure, thread grooves for screwing with fixing screws 135 explained later of the coupling members 13 are formed in inner peripheral surfaces of the coupling projections 74. The coupling projections 74 are formed in a flat shape, both upper and lower sides of which extend along the horizontal surface.

Structure of the Second Moving Plate

FIG. 6 is a disassembled perspective view of the second moving plate 8, the fixed member 9, the first adjusting and driving unit 11, and the second adjusting and driving unit 12 viewed from the front side.

As shown in FIG. 6, the second moving plate 8 is made of a plate member of a substantial cross shape in plan view. The second moving plate 8 is movable in the left to right direction while coming into contact with the first moving plate 7 and the fixed member 9 between the first moving plate 7 and the fixed member 9. The second moving plate 8 engages with the first moving plate 7 and moves to move the first moving plate 7 in the left to right direction.

In the second moving plate 8, an opening 81 of a substantial elliptical shape that has a dimension in the left to right direction substantially the same as an inner diameter dimension of the opening 71 of the first moving plate 7, extends in the up to down direction, and allows the proximal end of the lens barrel 31 to be inserted through is formed substantially in the center.

In the second moving plate 8, two first columnar guide projections 82 inserted through the first guide engaging holes 73 are formed in association with the two first guide engaging holes 73 in end faces on the front side in upper and lower projecting sections.

Further, in the second moving plate 8, a columnar engaging projection 83 for engaging with a second slider 123 explained later, which configures the second adjusting and driving unit 12, is formed in an end face on the front side in a projection section on the left side.

Moreover, in the second moving plate 8, second guide projections 84 (see FIGS. 12A and 12B and FIGS. 13A and 13B) that are located on a straight line L (see FIGS. 12A and 12B and FIGS. 13A and 13B) substantially orthogonal to a center axis of the engaging projections 83 and along the left to right direction, extend along the left and right direction, and engage with the fixed member 9 are formed in end faces on the back side in left and right projecting sections.

Structure of the Fixed Member

The fixed member 9 is a member that is fixed in the projector 1 and supports the entire projection position adjusting device 5. As shown in FIG. 6, the fixed member 9 includes a fixed member main body 9A and two holding members 9B.

As shown in FIG. 6, the fixed member main body 9A is made of a plate member of a substantial rectangular shape in plan view.

In the fixed member main body 9A, an opening 91 that has a shape substantially the same as the opening 81 of the second moving plate 8 and allows the proximal end of the lens barrel 31 to be inserted through is formed substantially in the center.

In the fixed member main body 9A, swelling sections 92 that have a rectangular shape in plan view and swell to the front side are formed in four corner positions in an end face on the front side.

As shown in FIG. 4, in the fixed member main body 9A, recesses 921 of a rectangular shape in plan view dent to the front side are formed in association with the forming positions of the swelling sections 92 in an end face on the back side. The swelling sections 92 are formed in a container shape opened on the back side and can house the coupling members 13.

As shown in FIG. 6, through holes 922 that have a dimension smaller than an opening dimension of the inside and allow the coupling projections 74 of the first moving plate 7 to be inserted through are formed in distal ends of the swelling sections 92.

The distal ends of the swelling sections 92 are formed of planes substantially orthogonal to the projecting direction.

With the configuration explained above, the end face on the back side of the first moving plate 7 comes into contact with the end faces at the distal ends of the swelling sections 92 in a state in which the coupling projections 74 are inserted through the through holes 922.

In the fixed member main body 9A, an upper suspended section 93 suspended between the swelling sections 92 on the upper side and lower suspended section 94 suspended between the swelling sections 92 on the lower side are formed in the end face on the front side.

In the fixed member main body 9A, two second guide engaging holes 95 (see FIGS. 12A and 12B and FIGS. 13A and 13B) through which the second guide projections 84 are inserted are formed in association with the two second guide projections 84 on both the left and right sides across the opening 91 in the end face on the front side. As shown in FIGS. 12A and 12B and FIGS. 13A and 13B, the second guide engaging holes 95 are formed to have a length dimension in the left to right direction larger than that of the second guide projections 84.

With the configuration explained above, the second moving plate 8 is arranged in a loosely fit state in a space surrounded by the swelling sections 92, and the upper suspended section 93, the lower suspended section 94. The end face on the back side of the second moving plate 8 comes into contact with the end face on the front side of the fixed member main body 9A in a state in which the guide projections 84 are inserted through the guide engaging holes 95.

In the fixed member main body 9A, fixing sections 96 projecting to the outer side are formed on both the left and right sides, respectively. The fixing sections 96 are sections to which the first adjusting and driving unit 11 and the second adjusting and driving unit 12 are fixed, respectively.

Since the fixing sections 96 have the same shape, only the fixing section 96 on the right side is explained below.

A fitting section 961 that has a substantially rectangular frame shape and in which a first rail member 115 explained later of the first adjusting and driving unit 11 is fit is formed substantially in the center in an end face on the front side in the fixing section 96.

Three circular holes 962 (see FIG. 7) that pierce through end faces on the front side and the back side of the fixing section 96 and are arranged in parallel along the up to down direction are formed on the inner side of the fitting section 961.

Housing projections 963 (see FIGS. 6 and 7) that have a circular frame shape having a diameter dimension larger than that of the circular holes 962 and house first urging members 116 explained later of the first adjusting and driving unit 11 are formed in peripheral edges of the circular holes 962.

In the fixing section 96, pairs of holding-member fixing sections 964 that project larger than the fitting section 961 to the front side and fix the holding member 9B are formed on both the upper and lower sides of the fitting section 961, respectively. In FIG. 6, only the pair of holding-member fixing sections 964 formed on the lower side are shown.

In the fixed member main body 9A, dial supporting sections 97 of a substantially rectangular shape in plan view that extend along the horizontal surface are formed on both the left and right sides of the end face on the upper side, respectively. The dial supporting sections 97 are sections on which dials 111 and 121 are placed, respectively. When dial attaching members 98 are engaged with hooks 971 from above the dial supporting sections 97, the dials 111 and 121 are attached to the dial supporting sections 97.

In the dial supporting sections 97, through holes 972 that pierce through in up to down direction and through which one end sides of a first worm 112 and a second worm 122 forming the adjusting and driving units 11 and 12 are inserted are formed substantially in the centers, respectively.

As shown in FIG. 6, the two holding members 98 are formed as substantially tabular member having the same shape. The holding members 9B are disposed on the front side of the fixed member main body 9A. When four fixing screws 9B1 are screwed in each of the holding-member fixing sections 964, members of the adjusting and driving sections 11 and 12 are held by the holding members 9B and the fixing sections 96, respectively.

Structure of the First Adjusting and Driving Unit

FIG. 7 is a longitudinal sectional view of the structure of the first adjusting and driving unit 11.

The first adjusting and driving unit 11 is a unit that moves the first moving plate 7 in the up to down direction according to operation of the user and changes the projection position of the projection lens 3 in the up to down direction. As shown in FIG. 6 or FIG. 7, the first adjusting and driving unit 11 includes a first dial 111, a first worm 112, a first slider 113, a first leaf spring section 114, a first rail member 115, and two first urging members 116.

The first dial 111 is an operation unit that is partially exposed from the top of an upper case 21 and operated by the user. As shown in FIG. 6 or FIG. 7, the first dial 111 has a substantially columnar shape and is placed on the dial supporting section 97 such that a columnar shaft thereof faces the up to down direction.

In the first dial 111, an end face on the upper side is formed in a concave shape dent in a substantially spherical shape. A tabular knob section 1111 that projects upward from the spherical surface and is operated by the user is formed on the end face on the upper side.

In the first dial 111, as shown in FIG. 7, a worm connecting section 1112 that is inserted through the through hole 972 of the dial supporting section 97 and connected to one end of the first worm 112 is formed substantially in the center of an end face on the lower side.

As shown in FIG. 6 or FIG. 7, the first worm 112 has a substantially columnar shape and crew threads 1121 are formed in a part of an outer circumference of the first worm 112. The first worm 112 is located on the holding member 9B side between the holding member 9B and the fixing section 96 and disposed such that a columnar shaft thereof faces the up to down direction. One end on the upper side of the first worm 112 is connected to the worm connecting section 1112 and the other end on the lower side thereof is connected between the pair of holding-member fixing sections 964 on the lower side. The first worm 112 rotates around the columnar shaft together with the first dial 111 according to operation by the user.

As shown in FIG. 6 or FIG. 7, the first slider 113 is formed in a substantial rectangular parallelepiped shape and disposed on the back side of the first worm 112. The first slider 113 converts the rotational force of the first dial 111 and the first worm 112 into linear moving force and moves the first moving plate 7 in the up to down direction.

In the first slider 113, thread grooves 1131 that screw with the first worm 112 are formed in a flat surface on the front side opposed to the first worm 112. When the screw threads 1121 and the thread grooves 1131 are screwed, the first slider 113 moves in the up to down direction along an extending direction of the first worm 112 according to the rotation of the first worm 112.

In the first slider 113, as shown in FIG. 6, a concave section 1132 that extends along the up to down direction and engages with the first rail member 115 is formed in an end face on the back side.

A detailed shape of the concave section 1132 is the same as that of the second slider 123 explained later of the second adjusting and driving unit 12. Therefore, the detailed shape is explained in the explanation of the second adjusting and driving unit 12 later.

As shown in FIG. 7, a housing recess 1133 for housing the first leaf spring section 114 is formed at the bottom of the concave section 1132.

Further, in the first slider 113, as shown in FIG. 7, a through hole 1134 that pierces through the bottom of the housing recess 1133 and an end face on the front side thereof (the bottom of the thread grooves 1131) is formed substantially in the center in the up to down direction.

Moreover, in the first slider 113, a first engaging protrusion 1135 of a substantial rectangular parallelepiped shape (FIG. 6) that is inserted through the engaging recess 72 of the first moving plate 7 and engages with the engaging recess 72 is formed on a left side surface.

As shown in FIG. 6 or FIG. 7, the first leaf spring section 114 has a rectangular shape in plan view. Both the upper and lower sides of the first leaf spring section 114 come into contact with the first rail member 115 while being housed in the housing recess 1133. Substantially the center in the up to down direction of the first leaf spring section 114 moves back and forth along the projecting direction with both the upper and lower sides thereof as fulcrums.

In the first leaf spring section 114, a projection 1141 inserted through the through hole 1134 is formed substantially in the center in the up to down direction on an end face on the front side.

Although not specifically shown in the figure, when the first slider 113 is located near a reference position while the first leaf spring section 114 is housed in the housing recess 1133 and moves in the up to down direction together with the first slider 113, the projection 1141 is pressed to the opposite side of the projecting direction by a contact section having a height dimension larger than other sections in the screw threads 1121 of the first worm 112. When the first slider 113 reaches the reference position, the projection 1141 engages with a recess formed in the contact section and the pressed state of the first leaf spring section 114 by the contact section is released. When the pressed state is released, since the projection 1141 engages with the recess, slight vibration occurs in the first worm 112. The user senses the vibration in the first worm 112 via the first dial 111. The user rotates the first dial 111 to recognize that the first slider 113 reaches the reference position, i.e., the projection lens 3 reaches a reference position in the up to down direction.

The reference position is set in the center of a moving range in the up to down direction of the projection lens 3.

As shown in FIG. 6 or FIG. 7, the first rail member 115 is made of a plate member of a rectangular shape in plan view in association with the shape of the fitting section 961 and fits in the fitting section 961. The first rail member 115 engages with the first slider 113 in an end face on the front side and guides the movement in the up to down direction of the first slider 113.

In the first rail member 115, as shown in FIG. 6, a convex section 1151 that extends along the up to down direction in association with the concave section 1132 and engages with the concave section 1132 is formed in the end face on the front side.

A detailed shape of the convex section 1151 is the same as that of a second rail member 125 explained later of the second adjusting and driving unit 12. Therefore, the detailed shape is explained in the explanation of the second adjusting and driving unit 12 later.

In the first rail member 115, as shown in FIG. 7, three cylindrical through sections 1152 that have an outer diameter dimension substantially the same as an inner diameter dimension of the three circular holes 962 and are inserted through the third circular holes 962, respectively, are formed in an end face on the back side.

Although not specifically shown in the figure, thread grooves for screwing with fixing screws 1153 are formed in inner circumferential surfaces of the through sections 1152. The first rail member 115 is attached to the fixing section 96 by screwing the two fixing screws 1153 from distal ends of the two through sections 1152 on both the upper and lower sides in a state in which the through sections 1152 are inserted through the circular holes 962 and fit in the fitting section 961, as shown in FIG. 7.

As shown in FIG. 7, the through sections 1152 are formed to have a projection dimension larger than a length dimension from the distal ends of the housing projections 963 to edges on the back side of the circular holes 962. Therefore, a gap is formed between the end face on the back side of the first rail member 115 and the distal ends of the housing projections 963 in a state in which screw heads of the fixing screws 1153 are in contact with peripheral edges of the circular holes 962. The first rail member 115 is movable by a distance of the gap along the projecting direction in a state in which the first rail member 115 is attached to the fixing section 96.

As shown in FIG. 6 or FIG. 7, the two first engaging members 116 are made of coil springs. As shown in FIG. 7, the first urging members 116 are housed in the two housing projections 963 on both the upper and lower sides in a state in which the two through sections 1152 on both the upper and lower sides are inserted through the first urging members 116. One ends of the first urging members 116 come into contact with the peripheral edges of the circular holes 962 and the other ends thereof come into contact with the end face on the back side of the first rail member 115. The first urging members 116 urge the first rail member 115 in the projecting direction.

Structure of the Second Adjusting and Driving Unit

-   -   FIG. 8 is a transverse sectional view of the structure of the         second adjusting and driving unit 12.

The second adjusting and driving unit 12 is a unit that moves the second moving plate 8 in the left to right direction according to operation of the user and, when the first moving plate 7 moves in association with the movement of the second moving plate 8, changes the projection position of the projection lens 3 in the left to right direction. As shown in FIG. 6 or FIG. 8, the second adjusting and driving unit 12 includes the second dial 121 (FIG. 6), the second worm 122, the second slider 123, a second leaf spring section 124 (FIG. 6), a second rail member 125, and two second urging member 126.

The members 121, 122, and 124 to 126 and the members 111, 112, and 114 to 116 of the first adjusting and driving unit 11 have the same shapes, respectively. Therefore, the second slider 123 is mainly explained below and explanation of the other members 121, 122, and 124 to 126 is omitted.

After the explanation of the second slider 123, a detailed shape of the convex section 1151 of the second rail member 125 is explained.

The second slider 123 converts the rotational force of the second dial 121 and the second worm 122 into linear moving force and moves the second moving plate 8 in the left to right direction.

As shown in FIG. 6 or FIG. 8, in the second slider 123, as in the first slider 113, the thread grooves 1131, the concave section 1132, the housing recess 1133 (not shown), and the through hole 1134 (no shown) are formed.

As shown in FIG. 8, the concave section 1132 is chamfered in corner sections on both the sides in the left to right direction to increase a width dimension in the left to right direction toward the back side and has slopes 1132A.

In the second slider 123, a second engaging protrusion 1235 of a substantial rectangular parallelepiped shape through which the engaging projection 83 of the second moving plate 8 is inserted and that engages with the engaging protrusion 83 is formed on the right side.

In the second engaging protrusion 1235, an inclining engaging hole 1236 that pierces through end faces on the front side and the back side and through which the engaging projection 83 is inserted is formed.

The inclining engaging hole 1236 is formed to cross the left to right direction and the up to down direction and extend from lower left to upper right in a plane orthogonal to the projecting direction (see FIG. 6, FIGS. 12A and 12B, and FIGS. 13A and 13B).

As shown in FIG. 8, the convex section 1151 corresponds to the concave section 1132. The convex section 1151 is chamfered in corner sections on both the sides in the left to right direction to increase a width dimension in the left to right direction toward the back side and has slopes 1151A.

Structure of the Coupling Members

FIG. 9 is a disassembled perspective view of a state in which the first moving plate 7 is attached to the fixed member 9 by the four coupling members 13 viewed from the front side.

As shown in FIG. 9, the four coupling members 13 are disposed in the respective swelling sections 92 from the back side of the fixed member main body 9A. The coupling members 13 are connected to the coupling projections 74 inserted through the through holes 922, respectively, and the peripheral portion of the through holes 922 and attach the first moving plate 7 to the fixed member 9. The coupling members 13 have the same structure. Each of the coupling members 13 includes a first pressing member 131, a second pressing member 132, a coil spring 133, a washer 134, and a fixing screw 135.

The first pressing member 131 is a member that comes into contact with the peripheral portion of the through hole 922 and is formed in a substantially rectangular shape. Although not specifically shown in the figure, a length dimension in the left to right direction (a long side direction) of the first pressing member 131 is set substantially the same as an opening dimension in the left to right direction of the recess 921. A length dimension in the up to down direction (a short side direction) thereof is set smaller than an opening dimension in the up to down direction of the recess 921.

In the first pressing member 131, a first through hole 1311 that extends in the left to right direction and through which the coupling projection 74 is inserted is formed substantially in the center. An inner diameter dimension in the up to down direction of the first through hole 1311 is set substantially the same as an outer diameter dimension in the up to down direction of the coupling projection 74. An inner diameter dimension in the left to right direction thereof is set larger than an outer diameter dimension in the left to right direction of the coupling projection 74.

The second pressing member 132 is a member that comes into contact with an end face on the back side in the first pressing member 131 and is formed in a bottomed cylindrical shape opened on the back side.

In the second pressing member 132, a second through hole 1321 that has an inner diameter dimension substantially the same as an outer diameter dimension of the coupling projection 74 and through which the coupling projection 74 is inserted is formed in a bottom section.

The coil spring 133 is disposed in the second pressing member 132 in a state in which the coupling projection 74 is inserted through the coil spring 133. One end of the coil spring 133 comes into contact with the bottom section of the second pressing member 132 and the other end thereof comes into contact with the washer 134. The coil spring 133 urges the washer 134 in a direction away from the second pressing member 132.

The fixing screw 135 is screwed from the distal end of the coupling projection 74 via the washer 134 in a state in which the coupling projection 74 is inserted through the through hole 922, the first pressing member 131, the second pressing member 132, and the coil spring 133. Consequently, the pressing members 131 and 132 are pressed against the peripheral portion of the through hole 922 by the urging force of the coil spring 133. The washer 134, the fixing screw 135, and the coupling projection 74 are pressed against the opposite side of the projecting direction by the urging force. In other words, the first moving plate 7 is drawn to the opposite side of the projecting direction and attached to the fixed member 9.

Operations of the Projection Position Adjusting Device

Operations of the projection position adjusting device 5 explained above are explained.

An up to down motion of the first moving plate 7 by the first adjusting and driving unit 11 and a left to right motion of the moving plates 7 and 8 by the second adjusting and driving unit 12 are explained below in order.

Up to Down Motion

FIGS. 10A and 10B and FIGS. 11A and 11B are diagrams for explaining the up to down motion. Specifically, FIGS. 10A and 10B are diagrams of a state in which the first moving plate 7 moves to an upper side. FIGS. 11A and 11B are diagrams of a state in which the first moving plate 7 moves to a lower side. FIGS. 10A and 11R are diagrams viewed from the front side. FIGS. 10B and 11B are sectional views taken along a X-X line shown in FIG. 10A and a XII-XII line shown in FIG. 11A, respectively.

FIGS. 10A and 10B and FIGS. 11A and 11B, for convenience of explanation, the projection lens 3 and the lens connecting unit 6 are not shown.

As shown in FIGS. 10A and 10B and FIGS. 11A and 11B, in a state in which the projection position adjusting device 5 is assembled, the first engaging protrusion 1135 and the engaging recess 72 are engaged. Therefore, when the first dial 111 is rotated by the user, the first moving plate 7 moves in the up to down direction in association with the first slider 113. When the first moving plate 7 moves, inner circumferences of the first guide engaging holes 73 come into slide contact with outer circumferences of the first guide projections 82 formed in the second moving plate 8 and the movement in the up to down direction of the first moving plate 7 is guided.

When the first moving plate 7 moves in the up to down direction, the projection position of the projection lens 3 connected to the first moving plate 7 via the lens connecting unit 6 is changed in the up to down direction.

Left to Right Motion

FIGS. 12A and 12B and FIGS. 13A and 13B are diagrams for explaining the left to right motion. Specifically, FIGS. 12A and 12B are diagrams of a state in which the second moving plate 8 moves to the left side. FIGS. 13A and 13B are diagrams of a state in which the second moving plate 8 moves to the right side. FIGS. 12A and 13A are diagrams viewed from the front side. FIGS. 128 and 13B are sectional views taken along a XII-XII line (a straight line L) shown in FIG. 12A and a XIII-XIII line (a straight line L) shown in FIG. 13A, respectively.

In FIGS. 12A and 12B and FIGS. 13A and 13B, for convenience of explanation, the first moving plate 7 and the first slider 113 are not shown in addition to the projection lens 3 and the lens connecting unit 6.

As shown in FIGS. 12A and 12B, in a state in which the projection position adjusting device 5 is assembled, the inclining engaging hole 1236 and the engaging projection 83 are engaged. Therefore, when the second dial 121 is rotated in a predetermined direction by the user and the second slider 123 moves to the upper side, the engaging projection 83 is guided in the inclined engaging hole 1236 and the second moving plate 8 moves to the left side. When the second moving plate 8 moves, outer circumferences of the second guide projections 84 come into slide contact with inner circumferences of the second guide engaging holes 95 formed in the fixed member 9 and both upper and lower end faces thereof come into contact with the suspended sections 93 and 94 formed in the fixed member 9. The movement to the left side of the second moving plate 8 is guided.

As shown in FIGS. 13A and 13B, when the second dial 121 is rotated in an opposite direction of the predetermined direction by the user and the second slider 123 moves to the lower side, the engaging projection 83 is guided in the inclining engaging hole 123 and, conversely to the above, the second moving plate 8 moves to the right side.

Since the first guide projections 82 and the first guide engaging holes 72 are engaged, when the second moving plate 8 moves in the left to right direction, the first moving plate 7 moves in association with the second moving plate 8. When the first moving plate 7 moves, since the first engaging protrusion 1135 moves in the left to right direction back and forth in the engaging recess 72, the first moving plate 7 is not disengaged from the first slider 113. The projection position of the projection lens 3 is changed in the left to right direction according to the movement in the left to right direction of the first moving plate 7.

According to the embodiment explained above, there are effects explained below.

In this embodiment, the adjusting and driving units 11 and 12 respectively include the worms 112 and 122 that extend in the up to down direction and are arranged parallel to each other. Consequently, it is possible to expose the dials 111 and 121 from the top of the armor housing 2 by providing the dials 111 and 121 at one ends on the upper side of the worms 112 and 122. Therefore, operability of the projection position adjusting device 5 is improved and improvement of convenience in adjusting the projection position can be realized.

The adjusting and driving units 11 and 12 include the sliders 113 and 123. The first slider 113 engages with the engaging recess 72 of the first moving plate 7 in the first engaging protrusion 1135. The second slider 123 engages with the engaging projection 83 of the second moving plate 8 in the inclining engaging hole 1236. Therefore, even when the dials 111 and 121 are exposed from the top of the armor housing 2, it is possible to adjust the projection position without providing the transmission converting mechanism such as the pair of spiral gears in the past and realize simplification of the structure.

In the first slider 113, the thread grooves 1131 are formed in the flat surface opposed to the first worm 112. The first slider 113 is urged to the first worm 112 via the first rail member 115 by the first urging member 116. Consequently, when the force due to the own weight of the projection lens 3 is applied to the first slider 113 in the up to down direction via the first moving plate 7 by the impact due to the drop of the projector 1 or the like, the first slider 113 slips out of the threads 1121 of the first worm 112 and moves in the up to down direction while moving in the direction away from the first worm 112 against the urging force generated by the first urging member 116. Therefore, even in the case described above, it is possible to prevent the thread grooves 1131 of the first slider 113, the threads 1121 of the first worm 112, and the like from being damaged.

The second slider 123 is configured in the same manner as the first slider 113. The second slider 123 is urged to the second worm 122 via the second rail member 125 by the second urging member 126. The slopes 1132A and 1151A are respectively formed in the concave section 1132 and the convex section 1151 formed in the second slider 123 and the second rail member 125. Consequently, when the force due to the own weight of the projection lens 3 is applied to the second slider 123 in the left to right direction via the first moving plate 7 and the second moving plate 8 by the impact due to the drop of the projector 1 or the like, the second slider 123 slips out of the threads 1121 of the second worm 122 through the slopes 1132A and 1151A and moves in the left to right direction while moving in the direction away from the second worm 122 against the urging force generated by the second urging member 126. Therefore, even in the case described above, it is possible to prevent the thread grooves 1131 of the second slider 123, the threads 1121 of the second worm 122, and the like from being damaged.

The second guide projection 84 and the second guide engaging hole 95 formed in the second moving plate 8 and the fixed member 9 are located on the straight line L crossing the center axis of the engaging projection 83, which receives force from the second slider 123, and extending along the moving direction of the second moving plate 8. Consequently, the second moving plate 8 does not rotate in the plane orthogonal to the projecting direction when the second moving plate 8 moves according to the movement of the second slider 123. It is possible to smoothly move the second moving plate 8 in the left to right direction using the second guide projection 84 and the second guide engaging holes 95.

The first guide engaging hole 73 and the first guide projection 82 formed in the first moving plate 7 and the second moving plate 8 are located on a straight line L′ (FIGS. 10A and 10B and FIGS. 11A and 11B) present near the two projections 72A, which receives force from the first slider 113, and extending along the moving direction of the first moving plate 7. Consequently, the first moving plate 7 does not rotate in the plane orthogonal to the projecting direction when the first moving plate 7 moves according to the movement of the first slider 113. It is possible to smoothly move the first moving plate 7 in the up to down direction using the first guide engaging hole 73 and the first guide engaging projection 82.

The through sections 1152 in the first rail member 115 are inserted through the first urging member 116. In other words, an urging position to the rail member 115 by the first urging member 116 is set in substantially the same position as an attaching position of the first rail member 115 to the fixed member 9. Consequently, it is possible to urge in good balance the first rail member 115 in the projecting direction using the first urging member 116 and prevent the first rail member 115 from inclining with respect to the plane orthogonal to the projecting direction. In other words, since the first rail member 115 is set in the state described above, it is possible to satisfactorily guide the first slider 113 using the first rail member 115. The same holds true for the second adjusting and driving unit 12. It is possible to satisfactorily guide the second slider 123 using the second rail member 125.

The invention is not limited to the embodiment. Modifications, alterations, and the like are included in the invention as long as the objects of the invention can be attained.

In the embodiment, the worms 112 and 122 are disposed to extend in the up to down direction. However, the present invention is not limited to this. The worms 112 and 122 only have to be arranged in parallel to each other and, for example, may be disposed to extend in the left to right direction.

In the embodiment, the first moving plate 7 is moved in the extending direction of the worms 112 and 122 (the up to down direction) and the second moving plate 8 is moved in the direction orthogonal to the extending direction of the worms 112 and 122 (the left to right direction) by using the adjusting and driving units 11 and 12. However, the present invention is not limited to this. For example, the first moving plate 7 may be moved in the left to right direction by using an engaging structure same as the engaging structure of the second moving plate 8 and the second slider 123. The second moving plate 8 may be moved in the up to down direction by using an engaging structure same as the engaging structure of the first moving plate 7 and the first slider 113.

In the embodiment, the first moving plate 7 and the second moving plate 8 are attached to the fixed member 9 by the coupling members 13. However, the present invention is not limited to this. The coupling members 13 may be omitted and an auxiliary plate that holds the first moving plate 7 and the second moving plate 8 between the auxiliary plate itself and the fixed member 9 may be provided. When the auxiliary plate is provided, positions of the first moving plate 7 and the second moving plate 8 are not limited to the positions explained in the embodiment. The first moving plate 7 may be arranged between the second moving plate 8 and the fixed member 9.

In the embodiment, the inclining engaging hole 1236 may be provided in the second moving plate 8 and the engaging projection 83 may be provided in the second slider 123.

In the embodiment, the convex sections 1151 may be provided in the sliders 113 and 123 and the concave sections 1132 may be provided in the rail members 115 and 125. The slopes 1132A and 1151A may be provided in at least one of the concave sections 1132 and the convex sections 1151.

In the embodiment, the second guide engaging hole 95 may be provided in the second moving plate 8 and the second guide projection 84 may be provided in the fixed member 9. Similarly, the first guide engaging hole 73 may be provided in the second moving plate 8 and the first guide projection 82 may be provided in the first moving plate 7.

In the embodiment, a shape of the sliders 113 and 123 is not limited to the shape explained in the embodiment. For example, the sliders 113 and 123 may be formed in a cylindrical shape surrounding the outer circumferences of the worms 112 and 122. Thread grooves may be formed in cylindrical inner circumferential surfaces of the sliders 113 and 123.

In the embodiment, the transmissive liquid crystal panel is adopted as the optical modulation device. However, the invention is not limited to this. A reflective liquid crystal panel, a DMD (Digital Micromirror Device) (a trademark of Texas Instruments Incorporated in the United States), or the like may be adopted.

In the embodiment, only an example of a front projection projector is explained. However, the invention is also applicable to a rear projection projector that includes a screen and projects light from the back side of the screen.

In the invention, it is possible to realize simplification of the structure of the projection position adjusting device and realize improvement of convenience in adjusting the projection position. Therefore, it is possible to use the invention in projectors used for presentation and home theaters.

The entire disclosure of Japanese Patent Application No. 2008-012937, filed Jan. 23, 2008 is expressly incorporated by reference herein. 

1. A projector comprising: a projection optical device that magnifies and projects image light; and a projection position adjusting device that moves the projection optical device in a plane orthogonal to a projecting direction and adjusts a projection position of the projection optical device, wherein the projection position adjusting device includes: a first moving plate that supports the projection optical device and moves in a first direction and a second direction orthogonal to each other in the plane orthogonal to the projecting direction; a second moving plate that engages with the first moving plate and moves in the second direction together with the first moving plate; adjusting and driving units that move the first moving plate and the second moving plate; and a fixed member that is fixed in the projector and supports the moving plates and the adjusting and driving units, the adjusting and driving unit include: a pair of worms that have a columnar shape and have threads on outer circumferences thereof; and a pair of sliders that are screwed in the pair of worms, respectively, and move in an extending direction of the worms according to the rotation of the worms, the pair of worms are disposed to extend along the first direction or the second direction, one of the sliders engages with one of the moving plates to move in the extending direction of the worms together with the one moving plate, and engaging structures including inclining engaging holes that extend in a direction crossing the direction in the plane orthogonal to the projecting direction and engaging projections inserted through the inclining engaging holes are provided in the other slider and the other moving plate.
 2. The projector according to claim 1, wherein the one slider has a flat first end face opposed to the worm, thread grooves that screw with the worm being formed in the first end face, and the adjusting and driving units include: a first rail member that is connected to the fixed member, engages with the one slider, and guides the movement of the one slider, and a first urging member that is interposed between the first rail member and the fixed member and urges the first rail member to the one slider.
 3. The projector according to claim 1, wherein the other slider has a flat second end face opposed to the worm, thread grooves that screw with the worm being formed in the second end face, the adjusting and driving units include: a second rail member that is connected to the fixed member, engages with the other slider, and guides the movement of the other slider, and a second urging member that is interposed between the second rail member and the fixed member and urges the second rail member to the other slider, engaging structures that extend along the worm and have a convex section and a concave section engaging with each other are provided in the other slider and the second rail member, and in at least one of the convex section and the concave section, slopes are formed in at both ends that cross in a direction orthogonal to the extending direction of the worm.
 4. The projector according to claim 1, wherein the other moving plate is arranged to be interposed between the fixed member and the one moving plate, the inclining engaging hole is provided in the other slider, the engaging projection is provided in the other moving plate, and engaging structures having guide engaging holes and guide projections that are located on a straight line crossing a center axis of the engaging projection and extending along the moving direction of the other moving plate, engage with each other, and guide the movement of the other moving plate with respect to the fixed member are provided in the other moving plate and the fixed member. 